Clamping device



Feb.y 4,1941.

G. E. TEGERDINE CLAMPING DEVICE Filed June '4, 1940 s Patented Feb. 4, 194i e `PATIE-NT OFFICE CLAMPING DEVICE .George Edwin Tegerdine, Feltham, England, assignor to General Aircraft Limited, Feltham,

England iApplication June 4, 1940,r Serial No. 338,795 g In Great Britain October- 19, 1938 Claims.

This invention relates to clampingA devices, and a particular application is to such devices for holding together aplurality-4 of parts such as metal plates or structural members to facilitate 5 their assembly by riveting, bolting, or like operations. e e

The invention has a particular use in the manufacture of aircraft where metal plates are attached to a supporting structure or interattached l0 by solid or tubular rivets. In `the manufacture of .Stressed skin metal aircraft it often arises that the partslto be riveted are readily accessible from one face only, and in such cases tubular rivets are often used,being expanded by tools operated from the accessible f ace. It is desirable when assembling riveted structures that temporary clamps, which accurately align at least certain of the holes through Whichrivets are to be engaged (and thereby at least a large proportion of the series of rivet holes) are positioned so as to facilitate the riveting operation. v It is an object of the` invention to provide clamping devices for holding together a plurality of parts such as metal plates or structural members to facilitate their assembly by riveting.

It is a further object of the invention to provide a clamping device which may be readily positioned, for example from the outside or from the working face of a structure from which riveting is effected.

LYet a further -`object of the invention is to provide such Va clamping device which is simple in construction and readily positioned for use..

According to the presentinvention, a clamp to locate holes of structural parts to be united by l an operation such as rivetingincludesa member supporting an abutment for engagement with one free face of the parts to be assembled, and a second abutment carried by said'member and '40 movable in relation thereto, to engage the, op-`-A posite free face of said parts wherebyv to exert a clamping force thereon. Preferably, the member is adapted to extend through riveting holes formed, in the partsftovbe assembled, as forexample by including a part of rod or wire form,

and an abutmentomay conveniently be formed of such a rod or wire by turning over Yan extremity.

The turned-over' portion constitutes a foot which vcan be threaded through the rivet holes. vThe actual contact of an abutment with the surface may in certain cases be through a washer'or like auxiliary abutment surface,l for example slidably f supported on a rod or wire member of the clamping device. l o

Preferably, the means urging abutments'together is pivotally mounted upon a rod or wire member whereby it is readily swung in and out of clamping position, Whilst in cases where the rivet lhole is'somewhat larger in diameter than that of a rod or wire member, the latter may I5 support a sleeve of external diameter correspondfingrto the diameter of the rivet hole, so as to locate the abutment on the rod in engagement with the appropriate face of the work.

In cases where the rod or wire of the rivet 10 clamps engage through the rivet holes, the procedure when assembling the structure for riveting is generally such that the` clamps are engaged through certain or all of the holes through which the rivets are to be secured. The clamps 15 are then removed in turn, or in a certain predetermined order, the rivets being applied as each clamp is removed. Instead of placing the rivet clamps through the pairs or series of holes actually to be riveted, the structure may include 20 certain master holes for the reception of clamps .which can be left in position during the riveting,

bolting or like operation ready to be removed on completion.

In the accompanying drawing forming a part 25 of this specication and in which like numerals are employed to designate like parts throughout the same:

Figure 1 shows in perspective a clamping device incorporating an L-shaped spring providing the 30 second abutment; the ligure also indicates parts to beassembled by riveting;

Figure 2 shows in part section the parts clamped together by the device shown in Figure 1;

Figure 3 shows a modication of the clamping 35 device shown in Figures 1 and 2, illustrating a sleeve carried on the rod or wire member; and

Figure 4 is a detail View illustrating the sleeve with an abutment constituted by a flange thereof.

In eachof the Figures 1,2 and 3, the clamp- 40 ingdevice shown comprises a stii wire or rod l0 having a substantially straight portion and a .turned-over foot Il at its lower extremity which constitutes'a first abutment adapted to contact or press against the free face l2 on the under- 45 side of one of the parts I3 (indicated as a channel structural member) to which a metal plate I4 is to be attached by riveting. To that end, the rod member I0 extends through rivet holes I5. The second Vabutment is constituted by an 50 L-shaped spring I6 of leaf form, the angle of the bend between the limbs of which is somewhat less than The leaf spring is rolled over at its upper extremity l1 to embrace a pivot pin I8 disposed transverse to the longitudinal axis of 55 59 foot II engages the slit 24. whereafter the spring I9 around the pivot pin I8 so a's to be angularly movable relative to the spring. The spring is slit lengthwise down the centre of it to a point adjacent its outer extremity 2|. The width of the slit 20 is. approximately equal to the diameter of Y the wire I0 so that the wire can pass therethrough in swinging about the pivot pin I8. The limb 22 of the spring I6 forms the second abutment. and the length of wire between the pivot I8 and Afoot II is somewhat less than the corresponding length between the pin I8 and the limb 22 when the spring is uncompressed. `so that when the limb 22 is swung in with its extremity 2I in opposed relationship to the abutment II, as shown in Figure 2, a resilient clamping force is exerted, urging the parts I3 and Il together.

In using the clamp above described. and in particular that illustrated in Figures 1 and 2. the wire is pivoted to a position such as shown in Figure 1, and the foot is then threaded through the riveting holes. whereafter the wire is held substantially normally to the surface to be riveted. The spring is then moved angularly about the pivot provided by the Din I8 so that the abutment surfaces constituted bv the limbs 22 slide over the plate I4 or equivalent part to be riveted anddeform the spring. whereby a resilient clamping force is exerted between the two abutments, holding the parts firmly together.

In the modiiication shown in Figures 3 and 4, the rod Ill carries a sleeve 23 of diameter approximating to that of the rivet holes I5. This sleeve is slit longitudinally at 24 to allow the passage of the foot II. and it supports at its end nearer the pivot pins I8 a radial iiange 25. which constitutes in effect an auxiliary abutment through which the actual force of the abutment 22 is transmitted to the upper free surface of through the holes I5; the sleeve is then allowed to slide into the holes and is rotated so that the I6'can be moved angularly to the position shown in Figure 3 where it is r'formed. The abutment provided by the flange 25 may be ramped, as shown at 26, to facilitate the angular movement of the spring I6 about the pivot I8.

In certain cases it may be found desirable to use an auxiliary abutment in the form of a collar slidable on the rod I0 in the manner of the part 25,but not necessarily carrying a sie :ve such as 23.A Such an arrangement may enable pressure to be `applied to the surfacev in a uniformly distributed manner, whilst damage to the surface by the sliding movement of the spring may be prevented. In the arrangement shown in Figure 3, the foot 22 is spaced from the surface I4, and such spacing may be particularly convenient when using the device in the immediate vicinity of turned-up edges or iianges on parts to be riveted; the foot 22 in this case being spaced above the surface of the plate I4 to an extent sufficient to clear any up-turned edges.

It will be appreciated that the device described above provides a clamp which may be .readily applied for the purpose of accurately locating Dthe rod IU, which is bent over at its upper end plates orother parts to be riveted relatively to Yone another. The form of spring described may be arranged to be of a particularly strong clamping force, whilst at the same time no excessive Yeii'irt Ais required to position and compress the spring. The device as' a whole is simple and cheap in construction.

What I claim is:

1. A clamp to locate holes of structural parts, including a rod, an abutment xed on said rod for engagement with one free face of the parts. and a movable abutment comprising a bowed spring pivotally mounted on said rody said bowed spring being formed of sheet material and so mounted on said pivot that its surface is curved around the lines parallel to the axis of said pivot as centers, said bowed spring being swingable into a position in which it is engagedunder compression between its pivot and the free face of said parts remote from'said first-mentioned free face whereby to cooperate with said iixed abutment to effect clamping of said parts.

2.' A clamp to locate holes of structural parts. including a rod having an abutment at one end, and, swingable about a point towards the op posite end of said rod. a bowed spring having an overall natural length somewhat greater than the distance between said abutment and the point about which said spring is swingable; said bowed spring being formed of sheet material and so mounted on said pivot that itssurface is curved around the lines parallel to the axis of said pivot as centers, whereby said spring is swingable into a position in which it is held under compression to urge .the parts towards said abutment, and thereby effect clamping of the parts.

3. A clamp toY locate holes of structural parts, including a rod having an abutment at one end, and, swingable about a point near the other end of said rod, a bowed spring having an overall natural length4 somewhat greater than the distance between said abutment and the point about which the said spring is swingable, and a sep arate abutment; said bowed spring being formed of sheet material and so mounted on said pivot that its surface is curved around the lines parallel to the axis of said pivot as centers, said spring being swingable into a positionin which it is under compression, to clamp between it and said first abutment said parts with said separate abutment interposed between an exposed 4surface of said parts and a part of said clamp, to prevent scoring of said exposed surface by said clamp part. a

4. A clamp as set forth in claim 2, wherein the spring is substantially L-shaped, the foot portion thereof affording a surface for engagement with the free face remote fromgthat engaged by said fixed abutment.

5,. A clamp as set forth in claim 2, wherein said bowed spring is of leaf form, being split 'throughoutthe greater part of its length to accommodate the rod in swinging of the spring in relation thereto.

. 6. The combination of clamp and separate abutment as set forth in claim 3, in which said separate abutment includes a part to enter the holes of the structurall parts and an enlarged head surface for interposition between a structural part surface and a cooperating abutment.

'7. A clamp as set forth in claim 1, in which said member is constituted by a rod of suiiiciently small diameter for insertion through said holes.,

aesoneo 3 8. A clamp to locate holes of structural parts, comprising a member, at least one abutment on said member for engagement with one free face of the parts, a pivot on said member spaced from said abutment and a movable abutment comprising a strip of resilient material having one end mounted on said pivot, said pivot having its axis parallel to the surface of the strip and transverse to the length ot the strip, and said strip `being bowed, said strip being swingable into a position in which -it is engaged between its pivot and the free face oi' said parts opposite said rst free face. 1

10. In a device as claimed inclaim 8 kin which y said member Vcomprises a rod and said strip' extends in the direction of its pivot onboth sides of the rod, said strip having therein a longitudinal slot opposite said rod, said slot terminat- 10 ing short of the free end o! said strip.-

Gnoaan nnwm"y TEGERDINE.- 

